Sharif Digital Repository

Current research studies the effect of electromagnetic field on reducing precipitation on membrane surface in reverse osmosis. Reverse osmosis is one of the most widely applied methods for water desalinization. Despite its advantages over other desalinization techniques, suffers from shortcomings such as blockage of membrane surface. Use of magnetic fields for reducing precipitation in process equipment, the so-called magnetic treatment, has been studied and practiced for decades. This research intends to study the effect of electromagnetic field on water and its mineral content, and the possibility of its application as a method for reducing precipitation and blockage in reverse osmosis... 

Petrochemicals, refineries and power plants are among the biggest water-consuming industries. Of all systems in mentioned complex, most water is consumed in the cooling tower system, of which the feed water of the cooling tower accounts for the largest portion of water demand. Drainage loss (blowdown) which constitutes the biggest portion of the feed water losses, varies greatly with changes in source water quality and cooling water treatment. Scarcity of water, large quantities of cooling tower blowdown water and increasing of water price lead to activities for blowdown water treatment to reuse. In this project two pre-treatment methods and two final membrane treatment methods were... 

In this project, modification of reverse osmosis membrane was investigated in order to reduce the biofouling in treatment of brackish water. Furthermore, the technique which is used to attain the favorable results is graft polymerization to modify the membrane’s surface with grafting acrylic acid as hydrophilic monomer onto polyamide exploited as last layer in reverse osmosis membrane. This technique is a free radical grafting, andfree radicals which are needed for grafting are provided by the redox system potassium persulfate-sodium metabisulfite which was used as initiator. To figure out the best concentration of acrylic acid, initiator and process time in order to achieve a new membrane... 

Reverse osmosis membrane one of the common methods used for water desalination, today membrane, thin film composite(TFC) include three layers, top the these layers named selection layer, this poly amid layer contacted with feed water, sensitivity to chlorine in polyamide layer lead to high membrane chlorine sensitive. Difference methods used for enhance the chlorine resistance in polyamide membrane that categorized in three general categories, covering and protection of sensitive areas method has best results in comparison to other methods. In this research protection method choose and used, material that used, sanitized by result from surface analysis of commercial membrane manufactured in... 

This research aims to construct a membrane using supercritical system which can be used in the process of brackish water filtration.
For this purpose solutions of polysulfone with desired concentrations were prepared and set to be stretched on glass or nonwoven polyester with adjustable thickness. Then the film of solution was transferred into supercritical cell. Carbon dioxide was used as anti-solvent and it causes super saturation in solution.
In order to investigate the effect of operating parameters on membrane structure, pore size and porosity were considered as a symbol of membrane structure. These parameters include cell pressure and polysulfone concentration.
Generally,... 

One of the encouraging technologies for resolving the lack of clean water in the world is forward osmosis process (FO). Reaching to a optimized development of FO membranes is essential to make fo process commercially viable.
This study’s aim is to develop a thin film composites (TFC) membrane with high FO performance (good water flux and high salt rejection) in order to seawater desalination.
Polyacrylonitrile (PAN), a hydrophilic polymer, is a less considered polymer in fabricating support layer for TFC FO membranes .TFC membranes consist of a selective polyamide active layer formed by interfacial polymerization on top of a support layer fabricated by non-solvent induced phase... 

In this study the main goal is preparing an appropriate UltraFiltration membrane from PolyVinyl Chloride for using as substrate in producing efficient Reverse Osmosis membranes to use in sea water desalination. each membrane should have some specifications to use it as reverse osmosis membrane’s substrate. One of the most important specifications is the appropriate pore sizes. To investigate this subject pure water flux and PolyEthylene glycol rejection of prepared membranes is tested. After investigation of this parameters and proving them, RO membranes are prepared using this membranes.
Salt rejection of Brackish water (2000ppm) and sea water (Persian gulf,32000ppm) are measured in... 

Surface modification of thin-film composite (TFC) polyamide reverse osmosis membrane was carried out using CO2-laser irradiation and Dielectric barrier discharge (DBD) plasma to improve performance and antifouling properties of the prepared RO membranes. Firstly, TFC polyamide RO membranes were synthesized via interfacial polymerization of trimesoyl chloride (TMC) and m-phenylenediamine (MPD) monomers over porous polysulfone ultrafiltration support. Next, CO2-laser irradiation with 10,000-40,000 pulses and DBD plasma with 15, 30, 60 and 90 seconds duration were used for the surface modification. The surface properties were characterized by ATR-FTIR, SEM, AFM, and contact angle measurements.... 

The aim of this project is to achieve a semi permeable high flux membrane with a reasonable salt rejection for the treatment of low osmotic pressure water. A thin film composite membrane consists of three polymeric layers was studied in this project. These layers were polyester support, polysulfone sub layer and polyamine selective layer. The polyester support provides the mechanical resistance against the operating pressure. The polysulfone sub layer provides the suitable area for polyamide synthesize, and the polyamide layer is the selective active layer of membrane.
The resistance to water penetration in sub layer was reduced first and then, the pores in the polyamide layer refined by... 

The forward osmosis (FO) process is a high potential emerging membrane process in the seawater desalination and contaminated water treatment fields. One of the main challenges facing this process is the weak separation (high reverse solute flux, low water flux, and insufficient selectivity) and antifouling performances of its membranes. Various sections of this study focus on the development of FO membranes and their performance improvement. For this purpose, thin-film composite membranes with the same combination of polyethersulfone/polyamide (PES/PA) have been used to investigate the effect of metal-organic frameworks (MOFs) introduction on their performance. The support layer in all cases... 

In this study, two layer nanocomposite membrane of polyethersulfone (support layer) and polyamide (active layer) were prepared for the purpose of desalination of water by forward osmosis method. In order to take more advantage of this membrane, montmorillonite nanoparticles which had been modified by graphene oxide were placed in it. To bind the nanoparticle components together, at first, montmorillonite was functionalized by (3-Aminopropyl) triethoxysilane to increase its nucleophilicity, and for graphene oxide to increase its electrophilicity, thionyl chloride was added. The two compounds were mixed and stirred for 24 hours in the presence of triethylamine base by magnetic stirrer at 30°C... 

Membrane fouling is the main cause of permeate flux decline and loss of product quality in reverse osmosis (RO) systems, so good pretreatment of the feed solution was required to prevent membrane fouling. One of the most common applied pretreatment methods to prevent or control the scaling of different salts in feed water is to add scale inhibitors. Due to the great variety of commercial scale inhibitors RO plant operators must evaluate these chemicals before use in real plants. In this project three different types of antiscalants at concentrations of 10 ppm and one type of magnetic descaler on the RO pilot for the R.O plant feed water of agro-industrial Hakim Farabi evaluated and function... 

Vapor in agro-industry hakim farabi production electricity, Turbines force and thermal energy for Yellow and white sugar in sugar production. In the utilization to supply water for the boiler , condensate water return use Until plant be able to do its work ¬good quality of condensate water decrease cost of destruction energy in blow down and can save energy, reduce cost of chemical operation for optimum boiler water and costs associated with wastewater treatment. unclean condensate water consist of sugar and Electrical conductivity more than permissive is not suitable for use in The boiler because Increase the total dissolved solids and decreasing pH lower than the Extent permitted. The...